<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
		<style>
			.red {
				background-color: red !important;
			}
			.box1 {
				height: 500px;
				width: 500px;
				margin: 50px auto;
				border: 2px solid cadetblue;
			}
			.box2 {
				height: 300px;
				width: 300px;
				margin: 100px auto;
				border: 2px solid red;
			}
			
			.box3 {
				height: 100px;
				width: 100px;
				margin: 100px auto;
				background-color: aquamarine;
			}
		</style>
</head>
<body>


<div class="box1">
	<div class="box2">
		<div class="box3">
			
		</div>
	</div>
</div>







<script src="js/jquery-3.5.1.js"></script>
<script src="js/index.js"></script>
</body>
</html>